For Redis TLS connections, you can set up a client certificate or override the root certificate authority by configuring `tls` in your router's [YAML config file](https://www.apollographql.com/docs/router/overview/#yaml-config-file). For example:

```yaml
apq:
  router:
    cache:
      redis:
        urls: [ "rediss://redis.example.com:6379" ]
        #highlight-start
        tls:
          certificate_authorities: ${file./path/to/ca.crt}
          client_authentication:
            certificate_chain: ${file./path/to/certificate_chain.pem}
            key: ${file./path/to/key.pem}
        #highlight-end
```
